Alternating-current relay



C. V. DRYSDALE.

ALTERNATING CURRENT RELAY.

' APPLICATION FILED AUG-25, 1919- D 1,328,825, Patented Jan. 27, 1920.

5 SHEETS-SHEET l.

FIG. 2.

c. v. DRYSDALE.

ALTERNATING CURRENT RELAY.

APPLICATlON FILED AUG.25. 1919.

Patented Jan. 27; 1920.

' 5 SHEETSSHEET 2.

0. v. DRYSDALE.

ALTERNATING CURRENT RELAY.

APPLICATION FiLED AUG.25, 1919.

1,328,825, Patented Jan. 27, 1920.

5 SHEETS-SHEET 3.

C. V. DRYSDALE.

. ALTERNATING CURRENT RELAY.

APPLICATION FILED AUG-Z51 I919.

Patented Jan. 27, 1920.

5 SHEETS-SHEET 4.

FIGS.

F/GJQ.

C. V. DRYSDALE.

ALTERNATING CURRENT RELAY.

APPLICATION FILED AUG.25 1919.

1,328,825, Patented Jan. 27, 1920.

5 SHEETS-SHEET 5- N005 I, 5 I A D5 F/C.9.

072 Maw CHARLES VICKERY DRYSDALE, OF DUMBARTONSHIRE, SCOTLAND.

ALTERNATIN G-CURREN '1 RELAY.

Specification of Letters Patent.

Patented Jan. 2'7, 1920.

Application filed- August 25. 1919. Serial No. 319.583.

7 '0 all whom it may concern:

Be it known that'I, CHARLES VICKERY DRYsDALE, D. Sc, M. I. E. E., a subject ofthe King of England, and residing at Dumbartonshire, in Scotland,have invented certain new and useful Improvements in Alterhating-Current Relays, of which the following is a specification.

This invention relates to alternatingcun rent relays in which a contact is obtained by the operation of a small alternating current of definite frequency and refers particularly to relays which can be tunedby varying the strength of the magnetic field in which the vibratory member oscillates.

According to this invention the relay' works on the principle of tuning or resonance and the controlling magnetic field is varied for'the purpose of tuning either bymeans of a magnetlc shunt or by movement of the relay system between the poles ofa horse shoe magnet. An oscillating contactmaking magnetic needle is disposed between the poles of a permanent magnet and within a coil through which the alternating current passes. In order to obtain a continuous contact from the intermittent contact derived from this device a secondary relay may be.

provided comprising a highly damped moving coil which has a tangential rubbing contact. Since the oscillations of the magnetic needle cannot be damped without 10$ of sensitiveness it may be necessary to rovide means whereby contacts due to'mec anical disturbances may be avoided. This may be effected by mounting the coilthrough which the alternating current passes in pivots so that it can oscillate in the same plane as the needle, these oscillations being tuned by springs. Two contact members are then carried by this coil and so disposed that they can make contact with a contact-making arm carried by the needle when the latter oscillates as the results of current flowing through the coil around it. Mechanical disturbances of the device will then merely cause similar movements of all the contact members without contact between them oc curring. Alternatively, two similar permanent magnets may be employed and arranged with opposite polarity and with two similar magnetic needles suspended between the poles of the magnets both needles lying within the coil through which the alternating current passes. A single magnetic shunt is provided for the purpose of varying SlIIlllltaneously the fields of these magnets. The needles carry arms which are adapted to make contact together when the needles oscillate as a result of current flowing through the coil but mechanical disturbance will merely causelsimilar oscillations of the needies and their arms without contact occurring between the latter.

Also alternatively the double needle arrangement may be used with a single permanent magnet and magnetic shunt or with two magnets of similar polarities and operated by two coils in which the alternating current circulates in the'opposite sense, the needles carrying contact arms as described above.

The accompanying drawings illustrate by way of example several forms of relay constructed in accordance with this invention. In these drawings Figure 1 isa front view of one construction of the improved relay. F Fig. 2 is a section on the line 22 in Fig. 3 is a front viewof an alternative construction with which a secondary relay is combined.

FFig. 4 is a section on the line jlt in Fig. 5 is a front view partly in vertical section of a further alternative construction. Fig. 6 isa section on the line'6-6 in Fig. 5. i

,Fig. 7 is a part sectional front "elevation of the principal portions of yet another construction.

Fig. 8 is a vertical section on the line 8-8 in Fig. 7.

Fig. 9 is a horizontal section on the line 9-9 in Fig. 7.

Fig. 10 is'a front view partly in vertical section of a modification of the construction shown in Figs. 7, 8 and 9.

Fig. 11' is a section on the line 11-11 in Fig. 10.

Like letters indicate like parts throughout the drawings.

Referring to Figs. 1 and 2 a suitably mounted permanent horseshoe magnet A has fixed between its poles a coil B to which the ments or contacts E which in this construction are fixed in some convenient manner to the base on which the magnet A is mounted. The poles A of the magnet are arranged to give an intense field in the neighborhood of I the needle D and adjacent to these poles is a soft iron magnetic shunt F havin trol and the vibration frequency of the needle D and arm D can be varied. Suitable connections are arranged between the arm D and also the contacts E and two terminals G'to which are connected the local battery and secondary apparatus. The contacts E are adjustable so that the end of the of tuning the oscillations.

be marked on the member K;

arm D" will touch them lightly as it oscillates on either side of its stationary position and the range through which the arm D can oscillate is limited by rubber bufiers H.

In the construction illustrated in Figs. 3 and 4 the coil B together with the needle D and the contacts E are carried on a bracket J which can be moved along a vertical member K so that the position of the coil and needle between the poles of the 'magnet A can be altered and the needle set in magnetic fields of difierentstrengths for the purpose A scale of frequencies can Since the intermittence of the contacts between the arm D the device unsuitable for use in certain cases a continuous contact can be obtained by, means of a secondary moving coil relay as embodied in the construction shown in Figs. 3 and 4. A moving coil L is pivoted or suspended in some convenient manner between the poles A of the magnet the movements of the coil being highly damped by means of a copper former The coil carries a contact arm L the end of which makes tangential sliding contact with a hori- -zontally disposed brush of platinum filaments N. The oscillations of the arm L are limited in range by spring buflers 0. The arm D is in electrical connection with the coil L so that as the needle D oscillates and intermittent contact is made between the arm D and the contacts E an intermittent current will pass through the coil L from the local battery. This will result in contact between the arm L and this contact will be a continuous rubbingcontact since the arm L will swing through only a small arc owing to the inertia and damping of the coil L. Thus a steady current will flow through the contact arm L and the brush N.

In certain cases where the apparatus is liable to be subjected to mechanical disturbance it is necessary to provide some means.

to prevent such disturbances causing undeand filaments E rendersand the brush N sired contacts between the arm and the contact filaments. To obviate this the filaments may be mounted so that they can oscillate similarly to the needle and the arm. One method of effecting this is shown in the construction illustrated in Figs. 5 and 6.

Here the coil B is pivoted as at B between the poles of the magnet and the contacts or filaments E are carried by the coil and disposedso that they lie on either side of the contact arm D.

The movements of the coil B about its pivots are controlled by springs the members D and E An alternative construction that ma be adopted with a view to obviating the e ects of mechanical disturbance is shownin Figs. 7 to 9. In this case two similar horseshoe magnets A and A are employed anddisposed side by side with opposite polarity. The coil B lies between the poles of both ma nets and within the coil are twomagneti' c needles D and D arranged in accordance with the polarity of the magnets. The needle D has a contact arm D the end of which lies between twin contact arms D carried by the needle D the arms D and D being inclined toward each other as shown in Fig. 8. It will be apparent that any mechanical disturbance of the apparatus will afltect both. needles alike so that they will move similarly and undesired contacts will not occur. On the other hand the passage of the alternating current through the coil B will cause the needles to oscillate in opposite phase so that contact between the arms D and D will take place. In this construct on the field'of both magnets can be varied simultaneously by the -magnetic shunt F which can be moved between the poles of the A single horseshoe magnet A is employed.

with a magnetic shunt F but two coils B and B are used wound in opposite directions. Both coils lie between the poles of the magnet A and within the coils lie sim larly arranged magnetic needles D and D which respectively carry the contact armsD and D The relay when constructed as illustrated inFigs. 3 and 4 does not .as a rule require any compensating device since the coil L p in the secondary relay is so sluggish in its movements that contact will not be made between the arm L and the brush N until several contacts have been made between the arm D and the filaments E. I

The details of construction may be modifie'd to meet requirements and the purpose for which the apparatus is to be employed.

What I claim as my invention and desire to secure by Letters Patent is 1. In an alternating current relay working on the principle of tuning orresonance, the combination of a magnet, an oscillating contact-making needle disposed between the poles of said magnet, a coil surrounding said needle through which coil the alternating current passes, and means for varying the strength of the magnetic field in which the 'needle oscillates, for the purpose of tuning.

2. In an alternating current relay working 011 the principle of tuning or resonance, the combination of a magnet, an oscillating magnetic needle disposed between the poles of said magnet, a contact-making arm carried by said needle, contacts between which said arm vibrates, a coil surrounding said needle through which coil the alternating current passes, and means for varying the strength of the magnetic field in which the needle oscillates, for the purpose of tuning.

3. In an alternating current relay working on the principle of tuning or resonance, the combination of a magnet, an oscillating magnetic needle disposed between the poles of said magnet, a contact-making arm carried'by said needle, contacts between which said arm vibrates, a coil surrounding said needle through which coil the alternating current passes, means for varying the strength of the magnetic field in which the needle oscillates, for the purpose of tuning, a highly damped moving coil in the field of the magnet, a contact arm carried by 'such coil, and a fixed brush over which the contact arm makes continuous tangential rubbing contact through the action of the current derived from the intermittent contacts made by the oscillating system.

' 4. In an alternating current relay working on the principle of tuning or resonance, the combination of a magnet, an oscillating magnetic needle disposed between the poles of said magnet, a contact-making arm carried by said needle, a coil surrounding said needle through which coil the alternating current passes, pivots for said coil so that it can oscillate in the same plane as the needle, contacts carried by the coil and disposed one on each side of the arm carried by the needle, and means for varying the strength of the magnetic field in which the needle oscillates, for the purpose of tuning.

5. In an alternating current relay Work-.

ing on the principle oftuning or resonance, the combination of two similar permanent magnets arranged with opposite polarity,

two similar oscillating magnetic needles disposed respectlvely between the poles of the magnets, a coil surrounding both the needles through which coil the alternating current passes, contact arms carried by the needles and adapted to make contact together when the needles oscillate in opposite phase as a result of current flowin through the coil but also adapted to osci late together without making contact when such oscillations are the result of mechanical disturbance, and means for varying the strength of the magnetic'field in which the needles oscillate,

carried by the needles and adapted to make contact together when the needles oscillate in opposite phase as a result of current flowing through the coils but also adapted to oscillate together without making contact when such oscillations are the result of mechanical disturbance. 7

7. In an alternating current relay work ing on the principle of tuning or resonance, the combination of a magnet, an oscillating contact-making needle disposed between the poles of said magnet, a coil surrounding said needle through which coil the alternating current passes, and .an adjustable magnetic shunt for varying the strength of the magnetic field in which the needlev oscillates, for the purpose of tuning. 8. In an alternating current relay Working on the principle of tuning or resonance, the combination of a magnet, an oscillating magnetic needle disposed between the. poles of said magnet, a contact-m-aking arm .carried by said needle, contacts between whlch said arm vibrates, a 001i SllIl'OllIldlIlglSflld needle through which coil the alternating it can oscillate in the same plane as the' needle, contacts carried by the coil and disposed one on each side of the arm carried by the needle, and an adjustable magnetic shunt for varying the strength of the mag netic field inwhich the needle oscillates, for the purpose of tuning.

10. In an alternatin current relay Working on the principle oi tunin or resonance, the conibination of two similar permanent magnets arranged with opposite polarity, two similar oscillating magnetic needles disposed-respectively between the poles of the magnets, a coil surrounding both the needles through which coil the alternating current passes, contact arms carried by the needles and adapted to make contact together when the needles oscillate in opposite phase as a result of current flowing through the coil but also adapted to oscillate together without making contact when such oscillations are the result of mechanical disturbance, and

an adjustable magnetic shunt for varying the strength of the magnetic field in which the needles oscillate, for the purpose of tuning.

11. 'In" an alternating current relay work ing on the principle of tuning or resonance, the combination of a single permanent magnet, two similar oscillating magnetic nee-.

dles disposed between the poles of the magnet, two coils one surrounding each of the needles the winding and connection of the coils being such that an astatic system is formed, an adjustable magnetic shunt for varying the strength of the magnetic field in which the needle oscillates, for the purpose of tuning, and arms carried by the oscillations are the result of mechanical disturbance.

12. In an alternatin current relay working on the principle 0 tuning or resonance,

the combination of a magnet, an oscillating magnetic needle disposed between the poles of said magnet, a contact making arm carried by said needle, contacts between which said arm vibrates, a coil surrounding said needle through Which'coil the alternating current passes, means vfor alteri the position of the needle in relation to 51o magnet in order to vary the stren h of the magnetic field in which the ne le oscillates, for the purpose of tuning, a highly damped moving coil in the field of the magnet, a contact arm carriedhy such coil, and a fixed brush over which the contact arm makes continuous tangential rubbing contact through the action of vthe current derived from the intermittent contacts made by the oscillating system.

lln testimony whereof I sign my name to this specification. 4

CHARLES ncxmn DRYSDALE. 

